HIV-1 is the causative agent of AIDS. We have searched the available data bases for homology which may exist between the gp160 envelope protein of HIV-1, and proteins from man. The approach was taken to learn whether HIV-1 is acting as if it is a component of a host protein. A. Peptide synthesis - Peptides having homology between HIV-1 and a human protein, MHC Class II, were synthesized and conjugated to carrier proteins for immunization purposes. Fluorescence-conjugated peptides was prepared for visualization purposes and peptide-Sepharose conjugates were made for receptor isolation purposes. B. Receptor studies - Attempts are being made to isolate a receptor from CEM cells to which both MHC Class II and HIV-1 are believed to bind. The significance of this project lies in gaining an understanding of how HIV-1 binds to host cells. This may allow the targeting of anti HIV-1 drugs to specific cells which are vulnerable to HIV-1 and may identify potential targets for vaccine development.